Here's my list.
Will I be able to play most old games like Giana Sisters, IK+, Bubble Bobble, Ports of Call, Defender of The Crown etc? I've heard there's some kind of boot menu that can trick the games to think they're running on an A500 and the likes of that machine. Does this work for most games? Or will I be better off buying an A500 if I want to play these games?
Not that i know of. You run into some probz, with games that wont start on your A1200, it might be because they need a Kickstarter 1.3, and if they do, there nothing to, unless you can get hold of a Kickstarter switch.
You can get into a boot-menu by, holding either both mouse keys or one of them, when you start the Amiga, then you should get into a startup menu, which allow you to alter some things
If I want to add a HDD in the future, will I be needing some kind of interface to attach an ordinary IDE-drive or is it just to plug it in and boot?
If you're talking about a 3.5" IDE Hard disk, then you'll need a adaptor, like IDE Fix or PowerFlyer.
I've read about problems with the floppydrive in the late/relaunched A1200s. Any experience with these?
Not here.
Well my opinnion is: Congat with your A1200, i have had a lot of great time with mine. O great idea is get an accellorater card, a tower and a Mediator card.
The best of luck with the new Amiga,a nd welcome :-D :-D :-D